I bought the 90+ and 18t from Mike way back in about 2014. When I bought them the 90+ had been machined flat and so had the 18t. Im not sure why but they were and I think Mike had bought them like that when he lived in the US. The 18t ended up being no end of trouble and after 2 rebuilds and alot of smoke I gave it away. Fitted the 16t to the 18t's old hotside and had 2 years of troublefree (except for the mani leaks) running.
Took the mani off and sent it to a machine shop last year who said the number 1 runner had moved out of line with the rest and the turbo flange had a dip in it. Got all the parts back and thats when I noticed the slight slope in the stud area of the flange causing the gasket to not press flat.
Im sure I could find another machine shop or take it back and have it fixed but after having 6 years of stuffing around im just kind of over the whole setup and would rather go back to the stock setup that is proven to work. Ive just run out of patience with the seemingly endless stream of little problems with this mani and hotside and just want something that works without all the drama.
In regards to ported vs non ported there seem to be two camps with one saying it makes it quicker and others saying it makes it slower. Im going to give the non ported mani a try as ive only ever had ported so have no reference for the two side by side. Also having a look at the turbine inlet it does seem to make sense that the unported could flow better due to the gas velocity being kept high instead of the gas entering an expansion chamber and slowing down. Either way, im going to give it a go for science!
I wasnt going to literally throw a 90+ in the bin but this 90+ has overstayed its welcome has been voted off the island hahaha.